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"Implement Idle Shell history mechanism with History class"
from idlelib.configHandler import idleConf
class History:
''' Implement Idle Shell history mechanism.
store - Store source statement (called from PyShell.resetoutput).
fetch - Fetch stored statement matching prefix already entered.
history_next - Bound to <<history-next>> event (default Alt-N).
history_prev - Bound to <<history-prev>> event (default Alt-P).
'''
def __init__(self, text):
'''Initialize data attributes and bind event methods.
.text - Idle wrapper of tk Text widget, with .bell().
.history - source statements, possibly with multiple lines.
.prefix - source already entered at prompt; filters history list.
.pointer - index into history.
.cyclic - wrap around history list (or not).
'''
self.text = text
self.history = []
self.prefix = None
self.pointer = None
self.cyclic = idleConf.GetOption("main", "History", "cyclic", 1, "bool")
text.bind("<<history-previous>>", self.history_prev)
text.bind("<<history-next>>", self.history_next)
def history_next(self, event):
"Fetch later statement; start with ealiest if cyclic."
self.fetch(reverse=False)
return "break"
def history_prev(self, event):
"Fetch earlier statement; start with most recent."
self.fetch(reverse=True)
return "break"
def fetch(self, reverse):
'''Fetch statememt and replace current line in text widget.
Set prefix and pointer as needed for successive fetches.
Reset them to None, None when returning to the start line.
Sound bell when return to start line or cannot leave a line
because cyclic is False.
'''
nhist = len(self.history)
pointer = self.pointer
prefix = self.prefix
if pointer is not None and prefix is not None:
if self.text.compare("insert", "!=", "end-1c") or \
self.text.get("iomark", "end-1c") != self.history[pointer]:
pointer = prefix = None
self.text.mark_set("insert", "end-1c") # != after cursor move
if pointer is None or prefix is None:
prefix = self.text.get("iomark", "end-1c")
if reverse:
pointer = nhist # will be decremented
else:
if self.cyclic:
pointer = -1 # will be incremented
else: # abort history_next
self.text.bell()
return
nprefix = len(prefix)
while 1:
pointer += -1 if reverse else 1
if pointer < 0 or pointer >= nhist:
self.text.bell()
if not self.cyclic and pointer < 0: # abort history_prev
return
else:
if self.text.get("iomark", "end-1c") != prefix:
self.text.delete("iomark", "end-1c")
self.text.insert("iomark", prefix)
pointer = prefix = None
break
item = self.history[pointer]
if item[:nprefix] == prefix and len(item) > nprefix:
self.text.delete("iomark", "end-1c")
self.text.insert("iomark", item)
break
self.text.see("insert")
self.text.tag_remove("sel", "1.0", "end")
self.pointer = pointer
self.prefix = prefix
def store(self, source):
"Store Shell input statement into history list."
source = source.strip()
if len(source) > 2:
# avoid duplicates
try:
self.history.remove(source)
except ValueError:
pass
self.history.append(source)
self.pointer = None
self.prefix = None
if __name__ == "__main__":
from unittest import main
main('idlelib.idle_test.test_idlehistory', verbosity=2, exit=False)